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Publication numberUS3594514 A
Publication typeGrant
Publication dateJul 20, 1971
Filing dateJan 2, 1970
Priority dateJan 2, 1970
Publication numberUS 3594514 A, US 3594514A, US-A-3594514, US3594514 A, US3594514A
InventorsRobert C Wingrove
Original AssigneeMedtronic Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Hearing aid with piezoelectric ceramic element
US 3594514 A
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Description  (OCR text may contain errors)

United States Patent [72] Inventor Robert C. Wingrove Minneapolis, Minn. [21] Appl. No. 489 [22] Filed Jan. 2,1970 [45] Patented July 20, I971 [73] Assignee Medtronic, Inc. I

Minneapolis, Minn. Continuation of application Ser. No. 625,042, Mar. 22, 1967, now abandoned.

[541 HEARING AID WITH PIEZOELECTRIC CERAMIC ELEMENT 13 Claims, 4 Drawing Figs.

[52] US. Cl 179/107 R, 128/1 R [51] Int. Cl H04r 25/00 [50] Field oISearch 179/107; 128/1 R [56] References Cited UNITED STATES PATENTS 2,339,148 [/1944 Carlisle I79/107 2,995,633 8/1961 Puharich et a1 179/107 3,156,787 11/1964 Puharich et a1 3,170,993 2/1965 Puharich et al.... 179/107 3,209,081 9/ 1 965 Ducote et al. 179/ 107 3,346,704 10/ I 967 Mahoney 179/107 FOREIGN PATENTS 788,099 12/ I 957 England 179/107 OTHER REFERENCES Conservative Tympanoplasty," October 1, 1966, Geze J. Jako MD. and Claus Jensen M.D., A REPORT TO THE AMERICAN ACADEMY OF OPHTALMOLOGY AND OTOLARYNAOLOGY, Page 54 1 Primary Examiner-Kathleen H. Clat'fy Assistant Examiner-Randall P. Myers Attorneyl.'ew Schwartz ABSTRACT: Implantable hearing aid apparatus having a piezoelectric ceramic element mounted adjacent to the auditory conductive system of the middle ear for imparting vibra HEARING AID WITH PIEZOELECTRIC CERAMIC ELEMENT This is a continuation of application, Ser. No. 625,042 filed Mar. 22, I967 andnow abandoned.

BACKGROUND OF THE INVENTION Hearing aids have long been known in the field of medicalelectronics. Generally these known hearing aids are mounted external to the body and apply a vibration from a device mounted adjacent the external portion of the ear drum. While satisfactory for some uses, these known hearing aids are ineffective when the auditory system of the middle ear has become inoperative or highly inefficient. Some prior art attempts have been made to provide an implantable hearing aid by which the inoperative portions of the auditory system can be bypassed. These prior art systems used the technique of converting the vibration into air acoustics, and providing the vibrated air to the inner ear. These systems have the disadvantages of being inefficient and not capable of overcoming many common problems of inoperability of the auditory system, such as when the auditory ossicles are fused as pointed out in the publication Conservative Tympanoplasty," G. .I. .lako, MD. and C. Jansen, M.D., AMERICAN ACADEMY OF OPHTALMOLOGY AND OTOLARYNGOLOGY, IN STRUCTIONS SECTION, 1966.

To overcome these disadvantages the apparatus of this invention provides a piezoelectric ceramic element which is suitable for implantation in the middle ear structure of the body. Thus mechanical vibrations can be applied directly to the auditory system, such as the auditory ossicles or the oval window, or the vibrations can be caused at a predetermined spacing from the desired element of the auditory system.

SUMMARY OF THE INVENTION Briefly described, the apparatus of this invention comprises a piezoelectric ceramic element, described herein in its preferred embodiment as a bimorphic ceramic element, capable of transducing electrical signals to mechanical vibrations. The piezoelectric element is electrically connected to an electrical circuit which provides electrical signals to the piezoelectrical element representing the sound waves desired to be heard. The electrical circuit and the piezoelectric element are encapsulated in a substance inert to body fluids and tissue to avoid harmful effects from implantation in the body. The electrical circuit can be a receiver which receives electric signals from a transmitter located external to the body, or can be a complete unit which receives the sound waves through devices totally implanted, for transmission to the piezoelectric element.

IN THE DRAWINGS FIG. 1 is a view of an embodiment of the apparatus of this invention shown completely encapsulated;

FIG. 2 is a sectional view of a portion of the embodiment of FIG. I showing an encapsulated piezoelectric ceramic element;

FIG. 3 is a schematic drawing of the circuit of the embodiment of FIG. I; and

FIG. 4 is a block diagram of an external transmitter which can be used with the circuitry of FIG. 3.

DESCRIPTION OF FIGURES In FIG. 2 there is shown a sectional view of tall 13 and a portion of stem I2. Within tail 13 there is shown a piezoelectric transducer 15, here shown as a bimorphic ceramic element, similar to bimorphic elements used in phonograph pickup apparatus well known to those skilled in the electrical art. A pair of leads I6 and I7 are each shown connected to piezoelectric element 15, and extending through stem 12. Element I5 is shown encased in an epoxy 18. Element 15 and epoxy coating 18, as well as leads 16 and 17, are shown encapsulated in a substance 19 which is substantially inert to body fluids and tissue, such as silicon rubber. Preferably, the substance 19 around tail portion I3 is sufficiently thin so as to allow efficient translation of vibratory motion from transducer 15 to the auditory system of the middle ear, as more fully described below.

With respect to FIGS. I and 2 it should be understood that for purposes of clarity the drawings are not dimensionally accurate or in scale. For example, in one embodiment of this in vention which has been successfully tested, piezoelectric element 15 was 0.3-0.5 inches long; 0.05 inches wide; and 0.025 inches thick (including both layers of a bimorphic element); epoxy coating 18 around element 15 was approximately 0.01-0.015 inches thick; and substance 19 comprised a coating of about 0.01 inches thickness. The preceding dimensions are approximate.

Referring now to FIG. 3, there is shown a signal receiving coil 20. Connected in parallel with coil 20 is a capacitor 21. A diode 22 and a resistor 23 are connected in series across capacitor 21. Lead 16 connects from piezoelectric element 15 to a point between diode 22 and one side of resistor 23. Lead 17 connects between element 15 and the other side of resistor In FIG. 4 there is shown an exemplary block diagram of a transmitter used to provide signals to coil 20 of FIG. 3. In FIG, 4 there is shown a microphone 24, the output of which enters an audio preamplifier 25. Preamplifier 25 then provides a signal to a modulator 26 which in turn presents the modulated signal to an R-F oscillator 27. The output of oscillator 27 is transmitted through a transmitting coil 28 to coil 20 of FIG. 3.

OPERATION In the preferred embodiment disclosed herein, piezoelectric element 15 is a bimorphic element. That is, it is a ceramic element composed of two layers. When a voltage is applied between the two layers, that is across the bimorphic element, one of the layers tends to lengthen while the other tends to contract. Thus a bending is accomplished. It thus becomes apparent that the application of a varying voltage signal, such as one representing sound waves, will cause element 15 to bend or vibrate in response to the varying voltage signal. Element 15 is chosen to respond, or vibrate, in the audio frequency range, and is thus uniquely adapted to act as an electricalmechanical transducer in an implanted hearing aid.

The mode of vibration or bending is similar to that of a common diving board when the element used is substantially rectangular, as that shown in the preferred embodiment. As mentioned above, an element I5 can be chosen such that the frequency response covers the audio frequency range. The amount of bending or vibration is relatively small and is proportional to the amplitude of the applied signal. The bending force of an element such as element 15 is related to atomic crystal binding forces, and is thus relatively large and can overcome damping effects such as may be caused by epoxy coating 18 and silicon rubber coating 19.

It should be noted that epoxy coating 18 is shown here as part of the preferred embodiment for its function of adding further protection to the implanted device of this invention, such as added moisture protection. The apparatus of this invention will operate without epoxy coating 18. It should further be noted that greater efficiency of operation of the apparatus of this invention occurs when the portion of substance 19 encapsulating element 15 and its coating 18 in tail 13 of the apparatus is relatively thin, to avoid undue damping ef fects.

When mounting the apparatus 10 in a body, it is preferable to firmly mount one end of element (tail 13) in an area that can provide a stable platform, such as the mastoid bone. The other end of element 15 is then placed adjacent one of the elements of the auditory system of the middle ear, such as one of the auditory ossicles or the oval window. The free or vibrating end of element [5 can actually touch, or can be spaced from, the portion of the auditory system, as required. Head 11 can be mounted, for example, in the antrum cell of the mastoid, from which stem 12 can extend to tail 13 in the middle ear.

Referring to FIGS. 3 and 4, it can be seen that microphone 24 will transduce sound waves into electrical signals which will be amplified in preamplifier 25, modulated in modulator 26, and then passed on to R-F oscillator 27 whence it will be transmitted by coil 28. The apparatus of FIG. 4 is in this preferred embodiment intended to be located external to the body. However, as will be described below, it is possible to incorporate this entire hearing aid within an implantable device.

Coil 28 will transmit a modulated RF signal which will be picked up by the circuit comprising receiving coil and capacitor 21. The resulting voltage drop across capacitor 21 will be felt across diode 22 and resistor 23. Leads 16 and 17 connect element 15 across resistor 23. Diode 22 provides rectification or detection of the RF signal, and the combination of resistor 23 with the inherent capacitance of element 15 provides filtering of the RF signal leaving the resultant audio frequency modulation signal applied across element 15. Thus, as the transmitted signal varies in accordance with the varying sound waves picked up by microphone 24, a proportional varying voltage signal will be felt across element 15. This will cause bending or vibration of element 15 which will be mechanically transmitted directly to the auditory ossicle or oval window or other member of the auditory system of the middle ear.

If desired, and completely in keeping with the spirit of this invention, microphone 24 and amplifier 25 can be mounted within head 11 ofdevice 10 so that the entire hearing aid is implanted. This will remove the need for transmission and receiving coils 28 and 20, as well as modulator 26 and oscillator 27 and the associated electronic components described above, as will be obvious to those skilled in the art. Also, because a piezoelectric element such as element 15 can also be used as a microphone, microphone 24 can comprise another piezoelectric element, such as a bimorphic element, which transduces from mechanical to electrical signals.

The apparatus of this invention can also be used when it is necessary to remove completely the auditory ossicles of the middle car. This is a further example of the situation where it may be desirable to place vibrating element 15 adjacent the oval window.

ln summary, the apparatus of this invention provides a new and important hearing aid capable of implantation in the body, for imparting vibrations to one or more members of the auditory system of the middle car by means ofa piezoelectric element.

I claim:

1. In an implantable hearing aid including means for providing electrical signals representative of and derived from sound waves, piezoelectric ceramic means connected to receive the electrical signals, and further means operatively connected to said piezoelectric ceramic means and adapted to be mounted to contact a portion ofa middle ear of an animal.

2. The hearing aid of claim 1 in which said piezoelectric ceramic means comprises a bimorphic element.

3. The hearing aid of claim 1 in which said further means is adapted to be mounted to contact the auditory ossicles.

4. The hearing aid ol'claim l in which said further means is adapted to be mounted to contact the oval window.

5. The hearing aid of claim 1 in which said piezoelectric ceramic means is substantially rectangular and said piezoelectric ceramic means has one end adapted to be mounted to the mastoid bone In an ear of an animal, the other end connected to said further means adapted to extend to contact the portion of the middle ear of an animal for imparting vibrations thereto.

6. An implantable hearing aid comprising: electrical circuit means for providing electrical signals representative of sound waves; piezoelectric ceramic means for converting the electrical signals to mechanical vibrations; electrically conductive means connecting said circuit means to said piezoelectric means; all said means being encapsulated in a substance substantially inert to body fluids and tissue; said encapsulated piezoelectric ceramic means adapted to be mounted to contact a portion of the structure of the ear of an animal for imparting vibrations thereto.

7. The hearing aid of claim 6 in which said encapsulated piezoelectric ceramic means is operatively connected to further means adapted to contact a portion of the structure of the ear of an animal.

8. The hearing aid of claim 6 in which said piezoelectric ceramic means comprises a bimorphic element.

9. The hearing aid of claim 8 in which said bimorphic element is substantially rectangular and said bimorphic element has one end adapted to be mounted to the mastoid bone in an ear of an animal and the other end adapted to extend to contact a portion of the middle ear of an animal.

10. The hearing aid of claim 6 in which said electrical cir cuit means comprises electrical receiver means for receiving electrical signals from a transmitter external to the body in which the hearing aid is implanted.

11. The hearing aid of claim 6 in which said electrical circuit means includes mechanical-electrical transducer means for transforming sound waves into electrical signals.

12. The hearing aid of claim 11 in which said transducer means comprises second piezoelectric ceramic means.

13. The hearing aid of claim 12 in which said second piezoelectric ceramic means comprises a second bimorphic element.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2339148 *Dec 29, 1942Jan 11, 1944Sonotone CorpBone conduction receiver
US2995633 *Sep 25, 1958Aug 8, 1961Lawrence Joseph LMeans for aiding hearing
US3156787 *Oct 23, 1962Nov 10, 1964Lawrence Joseph LSolid state hearing system
US3170993 *Jan 8, 1962Feb 23, 1965Lawrence Joseph LMeans for aiding hearing by electrical stimulation of the facial nerve system
US3209081 *Oct 2, 1961Sep 28, 1965Behrman A DucoteSubcutaneously implanted electronic device
US3346704 *Dec 27, 1963Oct 10, 1967Jack L MahoneyMeans for aiding hearing
GB788099A * Title not available
Non-Patent Citations
Reference
1 *Conservative Tympanoplasty, October 1, 1966, Geze J. Jako M.D. and Claus Jensen M.D., A REPORT TO THE AMERICAN ACADEMY OF OPHTALMOLOGY AND OTOLARYNAOLOGY, Page 54
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3764748 *May 19, 1972Oct 9, 1973J BranchImplanted hearing aids
US4498461 *Dec 1, 1982Feb 12, 1985Bo HakanssonCoupling to a bone-anchored hearing aid
US4606329 *May 22, 1985Aug 19, 1986Xomed, Inc.Implantable electromagnetic middle-ear bone-conduction hearing aid device
US4628907 *Mar 22, 1984Dec 16, 1986Epley John MDirect contact hearing aid apparatus
US4982434 *May 30, 1989Jan 1, 1991Center For Innovative TechnologySupersonic bone conduction hearing aid and method
US5277694 *Feb 13, 1992Jan 11, 1994Implex GmbhElectromechanical transducer for implantable hearing aids
US5360388 *Oct 9, 1992Nov 1, 1994The University Of Virginia Patents FoundationRound window electromagnetic implantable hearing aid
US5411467 *May 30, 1990May 2, 1995Implex Gmbh SpezialhorgerateImplantable hearing aid
US5460593 *Aug 25, 1993Oct 24, 1995Audiodontics, Inc.Method and apparatus for imparting low amplitude vibrations to bone and similar hard tissue
US5498226 *Mar 5, 1990Mar 12, 1996Lenkauskas; EdmundasTotally implanted hearing device
US5554096 *Apr 8, 1994Sep 10, 1996SymphonixMethod of improving hearing in a subject
US5624376 *Jan 3, 1995Apr 29, 1997Symphonix Devices, Inc.Implantable and external hearing systems having a floating mass transducer
US5762583 *Aug 7, 1996Jun 9, 1998St. Croix Medical, Inc.Vibrator for an implantable hearing system
US5772575 *Sep 22, 1995Jun 30, 1998S. George LesinskiImplantable hearing aid
US5800336 *Jan 3, 1996Sep 1, 1998Symphonix Devices, Inc.Advanced designs of floating mass transducers
US5836863 *Aug 7, 1996Nov 17, 1998St. Croix Medical, Inc.Hearing aid transducer support
US5842967 *Aug 7, 1996Dec 1, 1998St. Croix Medical, Inc.Method for assisting hearing
US5857958 *Dec 23, 1996Jan 12, 1999Symphonix Devices, Inc.Implantable and external hearing systems having a floating mass transducer
US5879283 *Aug 7, 1997Mar 9, 1999St. Croix Medical, Inc.Implantable hearing system having multiple transducers
US5881158 *May 23, 1997Mar 9, 1999United States Surgical CorporationMicrophones for an implantable hearing aid
US5894651 *Dec 23, 1993Apr 20, 1999Trw Inc.Actuator/sensor package, graphite-epoxy laminate structures, bonding lead wire, non-conductive fiber, cured, aerospace applications
US5897486 *Mar 11, 1997Apr 27, 1999Symphonix Devices, Inc.Dual coil floating mass transducers
US5913815 *Dec 6, 1995Jun 22, 1999Symphonix Devices, Inc.For improving hearing
US5951601 *Mar 24, 1997Sep 14, 1999Lesinski; S. GeorgeAttaching an implantable hearing aid microactuator
US5977689 *Jul 18, 1997Nov 2, 1999Neukermans; Armand P.Biocompatible, implantable hearing aid microactuator
US5984859 *Apr 25, 1996Nov 16, 1999Lesinski; S. GeorgeImplantable auditory system components and system
US5997466 *Aug 7, 1996Dec 7, 1999St. Croix Medical, Inc.Implantable hearing system having multiple transducers
US6001129 *Aug 7, 1997Dec 14, 1999St. Croix Medical, Inc.Hearing aid transducer support
US6005955 *Aug 7, 1996Dec 21, 1999St. Croix Medical, Inc.Middle ear transducer
US6010532 *Nov 25, 1996Jan 4, 2000St. Croix Medical, Inc.Dual path implantable hearing assistance device
US6050933 *Nov 9, 1998Apr 18, 2000St. Croix Medical, Inc.Hearing aid transducer support
US6137889 *May 27, 1998Oct 24, 2000Insonus Medical, Inc.Direct tympanic membrane excitation via vibrationally conductive assembly
US6153966 *Sep 27, 1999Nov 28, 2000Neukermans; Armand P.Biocompatible, implantable hearing aid microactuator
US6171229Aug 7, 1996Jan 9, 2001St. Croix Medical, Inc.Ossicular transducer attachment for an implantable hearing device
US6261224May 3, 1999Jul 17, 2001St. Croix Medical, Inc.Piezoelectric film transducer for cochlear prosthetic
US6264603Aug 7, 1997Jul 24, 2001St. Croix Medical, Inc.Middle ear vibration sensor using multiple transducers
US6277148Feb 11, 1999Aug 21, 2001Soundtec, Inc.Middle ear magnet implant, attachment device and method, and test instrument and method
US6315710Jul 21, 1997Nov 13, 2001St. Croix Medical, Inc.Hearing system with middle ear transducer mount
US6436028Dec 28, 1999Aug 20, 2002Soundtec, Inc.Direct drive movement of body constituent
US6475134Jan 14, 1999Nov 5, 2002Symphonix Devices, Inc.Dual coil floating mass transducers
US6488616Apr 18, 2000Dec 3, 2002St. Croix Medical, Inc.Hearing aid transducer support
US6491722Jan 4, 2000Dec 10, 2002St. Croix Medical, Inc.Dual path implantable hearing assistance device
US6540662Jul 5, 2001Apr 1, 2003St. Croix Medical, Inc.Method and apparatus for reduced feedback in implantable hearing assistance systems
US6629922Oct 29, 1999Oct 7, 2003Soundport CorporationFlextensional output actuators for surgically implantable hearing aids
US6643378Mar 2, 2001Nov 4, 2003Daniel R. SchumaierBone conduction hearing aid
US6676592Nov 1, 2002Jan 13, 2004Symphonix Devices, Inc.Dual coil floating mass transducers
US6689045Dec 12, 2001Feb 10, 2004St. Croix Medical, Inc.Method and apparatus for improving signal quality in implantable hearing systems
US6726618Apr 12, 2002Apr 27, 2004Otologics, LlcHearing aid with internal acoustic middle ear transducer
US6730015Jun 1, 2001May 4, 2004Mike SchugtFlexible transducer supports
US6755778Oct 18, 2002Jun 29, 2004St. Croix Medical, Inc.Method and apparatus for reduced feedback in implantable hearing assistance systems
US6914994Sep 7, 2001Jul 5, 2005Insound Medical, Inc.Canal hearing device with transparent mode
US6940988Nov 25, 1998Sep 6, 2005Insound Medical, Inc.Semi-permanent canal hearing device
US6940989 *Dec 30, 1999Sep 6, 2005Insound Medical, Inc.Direct tympanic drive via a floating filament assembly
US7016504Sep 21, 1999Mar 21, 2006Insonus Medical, Inc.Personal hearing evaluator
US7302071Sep 15, 2004Nov 27, 2007Schumaier Daniel RBone conduction hearing assistance device
US7424124Apr 26, 2005Sep 9, 2008Insound Medical, Inc.Semi-permanent canal hearing device
US7664282Sep 27, 2005Feb 16, 2010Insound Medical, Inc.Sealing retainer for extended wear hearing devices
US7668325May 3, 2005Feb 23, 2010Earlens CorporationHearing system having an open chamber for housing components and reducing the occlusion effect
US7771642 *Apr 1, 2005Aug 10, 2010Novartis AgMethods of making an apparatus for providing aerosol for medical treatment
US7867160Oct 11, 2005Jan 11, 2011Earlens CorporationSystems and methods for photo-mechanical hearing transduction
US7876919Jun 29, 2006Jan 25, 2011Insound Medical, Inc.Hearing aid microphone protective barrier
US8068630Nov 26, 2007Nov 29, 2011Insound Medical, Inc.Precision micro-hole for extended life batteries
US8147544Oct 26, 2002Apr 3, 2012Otokinetics Inc.Therapeutic appliance for cochlea
US8150083Jul 7, 2008Apr 3, 2012Cochlear LimitedPiezoelectric bone conduction device having enhanced transducer stroke
US8294141Jul 7, 2009Oct 23, 2012Georgia Tech Research CorporationSuper sensitive UV detector using polymer functionalized nanobelts
US8295523Oct 2, 2008Oct 23, 2012SoundBeam LLCEnergy delivery and microphone placement methods for improved comfort in an open canal hearing aid
US8396239Jun 17, 2009Mar 12, 2013Earlens CorporationOptical electro-mechanical hearing devices with combined power and signal architectures
US8401212Oct 14, 2008Mar 19, 2013Earlens CorporationMultifunction system and method for integrated hearing and communication with noise cancellation and feedback management
US8401214Jun 18, 2010Mar 19, 2013Earlens CorporationEardrum implantable devices for hearing systems and methods
US8457336Jun 18, 2010Jun 4, 2013Insound Medical, Inc.Contamination resistant ports for hearing devices
US8494200Dec 15, 2010Jul 23, 2013Insound Medical, Inc.Hearing aid microphone protective barrier
US8503707Dec 23, 2009Aug 6, 2013Insound Medical, Inc.Sealing retainer for extended wear hearing devices
US8538055Feb 15, 2008Sep 17, 2013Insound Medical, Inc.Semi-permanent canal hearing device and insertion method
US8594356 *Apr 29, 2010Nov 26, 2013Cochlear LimitedBone conduction device having limited range of travel
US8620015May 20, 2008Dec 31, 2013Cochlear LimitedVibrator for bone conducting hearing devices
US8666101Nov 16, 2011Mar 4, 2014Insound Medical, Inc.Precision micro-hole for extended life batteries
US8682016Nov 23, 2011Mar 25, 2014Insound Medical, Inc.Canal hearing devices and batteries for use with same
US8696541Dec 3, 2010Apr 15, 2014Earlens CorporationSystems and methods for photo-mechanical hearing transduction
US8715152Jun 17, 2009May 6, 2014Earlens CorporationOptical electro-mechanical hearing devices with separate power and signal components
US8715153Jun 22, 2010May 6, 2014Earlens CorporationOptically coupled bone conduction systems and methods
US8715154Jun 24, 2010May 6, 2014Earlens CorporationOptically coupled cochlear actuator systems and methods
US20090043149 *Jan 13, 2006Feb 12, 2009Sentient Medical LimitedHearing implant
US20110268303 *Apr 29, 2010Nov 3, 2011Cochlear LimitedBone conduction device having limited range of travel
DE102009014770A1Mar 25, 2009Sep 30, 2010Cochlear Ltd., Lane CoveSchwingungserzeuger
DE102009014772A1Mar 25, 2009Sep 30, 2010Cochlear Ltd., Lane CoveHörhilfevorrichtung
WO1992012605A1 *Dec 27, 1990Jun 28, 1992Innovative Tech CenterSupersonic bone conduction hearing aid and method
WO1998006236A1 *Aug 7, 1997Feb 12, 1998St Croix Medical IncMiddle ear transducer
WO1999008480A2 *Aug 7, 1998Feb 18, 1999St Croix Medical IncMiddle ear transducer
WO2001050815A1Dec 28, 2000Jul 12, 2001Insonus Medical IncDirect tympanic drive via a floating filament assembly
Classifications
U.S. Classification600/25, 381/326
International ClassificationH04R25/00
Cooperative ClassificationH04R25/606
European ClassificationH04R25/60D1